The primary goal of this pilot study is the generation of pharmacokinetic profiles (oral bioavailability) - F, and metabolic clearance -CLt, in particular) of 2 distinct racial patient groups awaiting renal transplantation: caucasian and african americans. The secondary goal would be to establish a tacrolimus pharmacokinetic profile database where data from all types of organ transplant recipients can be utilized to provide a more effective set of guidelines for use of tacrolimus blood levels to aid optimization of dosing of the drug.